Cold chisel



July 2,1929. RAUKO 1919.449

COLD CHISEL Filed July 9, 1928 Patented July 2, 1929.

UNITED STATES JOSEPH BAUKO, 0F MILWAUKEE, WISCONSIN.

COLD CHISEL.

Application filed July 9, 1928. "Serial No. 291,365.

This invention relates to cold chiselsand is particularly directed to a cold chisel adapted to operate upon sheet metal.

When it is attempted to cut sheet metal with the usual type of cold chisel, it is found that the slit cut by the chisel is bordered on each side by a ragged edge. This edge is also fluted in an irregular manner and even if it is subsequently hammered, it nevertheless remains stretched and warped. One of the reasons why this result is produced is due to the fact that the chisel is forced as a wedge between the edges of the sheet metal and consequently forces these edges apart, thus puckering the edges.

Further, it is apparent that when the sheet metal is attached in such a manner that no firm support is located below the metal, it is impossible to cut the sheet metal with an ordinary cold chisel.

This invention is designed to provide a cold chisel which is adapted to cut sheet metal without stretching, fluting, or bending,

the edges of the metal, and is adapted to actually remove a strip of metal so that a slot of uniform width is produced.

Further objects are to provide a cold chisel which is adapted to out either straight or curved slots in sheet metal, so that it may be used to cut stencils or to sever a sheet of metal which is securely fastened in place without requiring any freedom of motion of the parts of the sheet metal and without requiring any support for the sheet metal.

Further objects are to provide a cold chisel having the characteristics enumerated above, which is easy to operate, which is simple and cheap to make and which is of sturdy formation.

Embodiments of the invention are shown in the accompanying drawings in which:

Figure 1 is a side view of a cold chisel embodying the invention;

Figure 2 is a top plan View of the end of the cold chisel;

Figure 3 is a bottom view; Figure 4 is a view to a comparatively. reduced scale showin a stencil'cut inthe sheet metal by the chise Figure 5 is a sectional view showing the chisel as it appears in relation to the sheet metal during the actual cuttin operation; Figure 6 is a side view of t e end of a modified form of chisel.

Referring to the drawings, it will be seen that the chisel comprises a body ortion 1 which is provided with a central orwardly and downwardly extending tongue 2 and with a pair of side tongues 3. These side tongues are located on opposite sides of the central tongue, as is obvious from Figures 2 and 3, and it is to be noted that the central tongue extends down below the bottom edge 4 of the side tongues 3, as is apparent from Figure 1.

The central tongue also widens as it approaches the body portion of the chisel, as is shown in Figure 2, and gradually merges into the body portion of the chisel, together with the side tongues.

It is to be noted also that the central tongue 2 is provided with a rounded lower portion. This lower portion is rounded at the sides indicated by the reference character 5 in Figure 3, and also at the bottom, as indicated by the reference character 6 in Figure 1. The rounding of the bottom of the central tongue permits the cutting of curved slots, as well as straight slots, as will be apparent as the description proceeds.

One form of work which the chisel is adapted to perform is indicated in Figure 4. This figure shows the sheet metal 7 provided with a stencil cut therein which may be in any form and, as illustrated, is the letter U, as indicated by the reference character 8. The chisel described is used to produce this type of work, when it is desired to produce a stencil or to cut a tongue in the metal. The chisel is merely driven along the metal with the bottom edges 4 of the side tongues riding flat upon. the metal, as shown in Figure 5, and with the central tongue 2 projecting below the bottom ed e of the sheet metal. The side tongues 3 0, not enter the metal at ally They merely ride on the upper surface of the metal. It has been found that the central tongue, as the chisel is driveinacross the sheet metal, rolls a strip of material 9, removed from the metal, up into a spiral, as shown in Figure 5.

In other words, the chisel bodily removes a strip from the sheet metal. Consequently, there is no swelling, fluting, or warpin of the adjacent edges of the sheet metal, where this chisel is used.

It is to be noted that there is a shearing action between the upper edges of the central tongue and the lower edges of the side tongue, as the chisel is driven across the metal, so that the metal is smoothly out between the tongues.

It is preferable-to provide slightly tapered or V-shaped notches or spaces 10 between the side tongues and the central tongue,

so that the adjacent edges of the central tongue and the side tongues gradually approach each other asthe metal moves inwardly along the chisel.

Further, due to the rounding of the bottom of the central tongue, it is obvious that the chisel may be used to cut curved slots in sheet metal. Further, the diverging or widening of the central tongue on its upper side also facilitates this operation.

It will be noted that by having the tongue tapered and widened at its inner end with. the side tongues diverging, it will allow the metal cutout to ride upwardly over the upper face of the central tongue 2, and due to the diverging relative the side tongues, the metal cutout may be readily turned to one side of the chisel or rolled up, as shown in Figure 5. The two side tongues will form a channel in which the metal will be guided and then due to the fact that the inner ends of the side tongues merge into the body at the inner end of the central tongue, the strip of metal to be out will be guided transversely to one side of the chisel.

In view of the fact that the side tongues 3 do not enter the metal, it is apparent that they may be made as indicated at 3 in the modified form shown in Figure 6. These side tongues are provided with roundedor squared forward ends or ends of any other desired shape, the rounded ends bein shown in the drawings. This manner of orming the side tongues is, of course, optional, depending upon the particular shape of the stock from which the chisel is formed.

It is apparent that a very simple and novel type of chisel has been. provided by this invention which may be used with the utmost ease to cut a smooth, uniform slot in sheet metal, without requiring any manipu-' lation or relative movement of the two portions into which the sheet metal is cut.

Further, it will be seen that this chisel may be used upon sheet metal without requiring any rigid support beneath the sheet metal.

It is to be noted also that there is no possible chance of swelling, fiuting, or bending the edges of the sheet metal when this chisel is used.

From actual use of this chisel, it has been found that the metal is cut with such smoothness, that no wire edges or ragged edges are left upon the adjacent edges of the severed metal. Also, it has been found that the chisel may be driven across the sheet metal with the utmost ease, as there is a distinct shearing action, and as the chisel does not wedge itself into the metal under any condition.

Further, the chisel has been successfully used to sever sheet metal or cut portions therefrom when the metal is secured inplace and cannot be shifted.

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention may be variously embodied and as the scope of such invention is to be determined as claimed.

I claim:

1. A cold chisel comprising a body portion having a central downwardly and forwardly extending tongue and having a pair of side tongues, said central tongue flaring on its upper side as the body portion is approached, said central tongue being adapted to bodily remove a strip of metal while the side tongues ride upon the sheet metal.

2. A cold chisel comprising a body portion havinga central downwardly and forwardly projecting tongue and having a pair of side tongues, said central tongue having a fiat upper face and having a rounded lower portion, whereby said cold chisel can cut straight or curved slots in the sheet metal.

3. A cold chiselcomprising a body portion having a central downwardly and forwardly projecting tongue and having a pair of side tongues laterally slightly diverging with reference to the side edges of said central tongue, said side tongues being adapted to ride upon the upper face of. the sheet metal and said central tongue being adapted to project below the sheet metal, whereby a strip of metal is removed by said central tongue as said cold chisel is driven across the sheet metal.

4. A cold chisel comprising a body portion having a central downwardly and forwardly projecting tongue, said tongue having rounded sides and a rounded bottom, a

pair of side tongues. upon opposite sides of the central tongue, with V-shaped notches between the side tongues and the central tongue whereby the adjacent edges of the centraltongue and the side tongues gradually approach each other and said central tongue having its outer end disposed below the ends of the side tongues.

5. A cold chisel comprising a body portion having a central downwardly and forwardly projecting tongue, said tongue having rounded side walls and a rounded bottom with its upper side flaring as the body portion .is approached and a pair of side tongues with their lower edges arranged above the transverse plane of the lower edge of the central tongue.

In testimony that I claim the foregoing I have hereunto set myv hand at Milwaukee, in the county of Milwaukee and State of Wisconsin. JOSEPH RAUKO. 

